Benchmark: JavaScript spread operator vs Object.assign performance (test 2)

Tests:

Using the spread operator
const firstObject = { sampleData: 'Hello world' } const secondObject = { moreData: 'foo bar' } const finalObject = { ...firstObject, ...secondObject };
Using Object.assign
const firstObject = { sampleData: 'Hello world' } const secondObject = { moreData: 'foo bar' } const finalObject = Object.assign({}, firstObject, secondObject);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Using the spread operator
Using Object.assign

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 11_0_1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/87.0.4280.88 Safari/537.36

Browser/OS: Chrome 87 on Mac OS X 11.0.1

View result in a separate tab

Test name	Executions per second
Using the spread operator	1860302.1 Ops/sec
Using Object.assign	4483367.0 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 2 months ago):

LLMs can make mistakes. Check important info.

Let's break down what's being tested in this benchmark.

**Benchmark Definition**

The benchmark is designed to compare the performance of two approaches: using the JavaScript spread operator (`...`) and `Object.assign` to merge two objects into a single object.

**Options Compared**

There are two options being compared:

1. **Using the spread operator**: This approach uses the syntax `const finalObject = { ...firstObject, ...secondObject };` to create a new object that inherits properties from both `firstObject` and `secondObject`.
2. **Using Object.assign**: This approach uses the method `const finalObject = Object.assign({}, firstObject, secondObject);` to create a new object by merging `firstObject` and `secondObject`.

**Pros and Cons**

* **Using the spread operator:**
	+ Pros:
		- More concise and readable syntax.
		- Less verbose than using `Object.assign`.
	+ Cons:
		- May have performance overhead due to the creation of a new object, even if it's not needed (as in this benchmark).
* **Using Object.assign:**
	+ Pros:
		- Can be more efficient for large objects or when performance is critical.
	+ Cons:
		- More verbose syntax.

**Library and Purpose**

In both test cases, no specific library is used. However, it's worth noting that `Object.assign` is a built-in method in JavaScript.

**Special JS Features/Syntax**

There are no special JavaScript features or syntax being used in this benchmark. The focus is on comparing the performance of two common approaches to merging objects.

**Other Considerations**

When designing benchmarks like this, consider factors such as:

* Garbage collection overhead
* Object size and complexity
* Browser/JavaScript engine variations
* Specific use cases (e.g., merging large datasets)

Keep in mind that benchmarking is an art, and different results may occur depending on various factors.

**Alternatives**

Other approaches to merging objects could be considered for alternative benchmarks:

1. **Destructuring**: Using destructuring syntax (`{ ...firstObject, ...secondObject }`) instead of the spread operator.
2. **Array methods**: Using `Array.prototype.concat()` or other array methods to merge objects.
3. **Custom merging functions**: Implementing a custom function to merge objects, potentially with optimizations for performance.

These alternatives could provide interesting insights into different aspects of object merging and performance optimization.

Related benchmarks:

JavaScript spread operator vs Object.assign performance (test 2) (version: 0)

Comparing performance of: Using the spread operator vs Using Object.assign

Created: 4 years ago by: Guest

Jump to the latest result

Using the spread operator

Using Object.assign

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 2 months ago):